Predictive Factors of Complete Tumor Response to First Line Chemotherapy in Patients with Extensive-stage Small Cell Lung Cancer

Abstract

Objective: We aimed to investigate the factors affecting the complete response (CR) rate and the effect of treatment response on survival in patients with extensive stage-small cell lung cancer (ES-SCLC) who received a combination of cisplatin and etoposide as first-line therapy. Method: This retrospective analysis included 140 ES-SCLC patients, who were followed in an oncology clinic. Patients were divided into two groups as CR and non-CR according to radiological evaluation after first line chemotherapy. Clinical and demographic characteristics and pretreatment hemogram parameters were obtained from electronic medical record system. Results: While CR was seen in 34 (24.3%) of all patients after the first line chemotherapy, 106 (75.7%) patients were in the non-CR group. On univariate analysis, predictors for CR to treatment were the absence of brain metastasis, receiving 6 chemotherapy cycles and good performance status (p<0.001; p=0.020; p=0.001, respectively). In multivariate analysis, the absence of brain metastasis and good performance status were independent predictive factors for CR (p=0.033; p=0.019, respectively). Better treatment response rate to first-line chemotherapy was found to be associated with improved disease-free survival, and overall survival (log-rank p<0.001; log-rank p<0.001, respectively). Conclusion: Good performance status and the absence of brain metastases were identified as independent predictive factors for CR in ES-SCLC patients at the time of diagnosis. Patients who achieved CR had a significantly longer survival rate than patients with lower treatment response.